The Effect of Strain Rate on Electrical and Mechanical Characteristics of Pure Aluminum Using Equal Channel Angular Pressing (ECAP)

-During equal-channel angular pressing (ECAP), the effect of severe plastic deformation (SPD) rate on both the electrical (electrical resistance, denoted as (R),Ω and The electrical resistivity denoted as (ρ), Ω.m) and mechanical characteristics (Ultimate Tensile Strength abbreviated as (UTS), MPa and Micro-Hardness measured in Vickers Hardness Number, abbreviated as VHN) of pure aluminum alloy are experimentally investigated.ECAP was used to improve the pure aluminum alloy\u27s microstructure at room temperature, which had samples with square cross sections. The findings indicate that as the rate of strain decreases from 0.3 to 0.1 s^-1, there is a gradual increase in both Ultimate Tensile Strength (UTS) and hardness, with the highest values observed at a strain rate of 0.025 s^-1.This study empirically explored the influence of ECAP on the macrostructure, microstructure, mechanical properties, and electrical properties of pure aluminum alloy at different strain rates (s^-1) – 0, 0.025, 0.1, and 0.3. In summary, it was observed that under the optimized ECAP conditions, specifically at a strain rate of 0.025 s^-1, the ultimate tensile strength increased by approximately 266%, micro-hardness by about 210%, and electrical resistivity by roughly 250% compared to the base material. The maximum value of the ultimate tensile strength was equal to 93 MPa, while the maximum value of hardness was equal to 41 VNN, and the maximum value of electrical resistivity was equal to 1.8 Ω.m, which is equivalent to the ratios mentioned above. Additionally, there was notable fragmentation of course second-phase particles and microstructure refinement

The Effect of Strain Rate on Electrical and Mechanical Characteristics of Pure Aluminum Using Equal Channel Angular Pressing (ECAP)

-During equal-channel angular pressing (ECAP), the effect of severe plastic deformation (SPD) rate on both the electrical (electrical resistance, denoted as (R),Ω and The electrical resistivity denoted as (ρ), Ω.m) and mechanical characteristics (Ultimate Tensile Strength abbreviated as (UTS), MPa and Micro-Hardness measured in Vickers Hardness Number, abbreviated as VHN) of pure aluminum alloy are experimentally investigated.ECAP was used to improve the pure aluminum alloy\u27s microstructure at room temperature, which had samples with square cross sections. The findings indicate that as the rate of strain decreases from 0.3 to 0.1 s^-1, there is a gradual increase in both Ultimate Tensile Strength (UTS) and hardness, with the highest values observed at a strain rate of 0.025 s^-1.This study empirically explored the influence of ECAP on the macrostructure, microstructure, mechanical properties, and electrical properties of pure aluminum alloy at different strain rates (s^-1) – 0, 0.025, 0.1, and 0.3. In summary, it was observed that under the optimized ECAP conditions, specifically at a strain rate of 0.025 s^-1, the ultimate tensile strength increased by approximately 266%, micro-hardness by about 210%, and electrical resistivity by roughly 250% compared to the base material. The maximum value of the ultimate tensile strength was equal to 93 MPa, while the maximum value of hardness was equal to 41 VNN, and the maximum value of electrical resistivity was equal to 1.8 Ω.m, which is equivalent to the ratios mentioned above. Additionally, there was notable fragmentation of course second-phase particles and microstructure refinement

Level of kidney function as a risk factor for atherosclerotic cardiovascular outcomes in the community

AbstractObjectivesThe goal of this study was to determine whether the level of kidney function is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD) outcomes in the Atherosclerosis Risk in Communities (ARIC) study, a prospective cohort study of subjects aged 45 to 64 years.BackgroundThe level of kidney function is now recognized as a risk factor for ASCVD outcomes in patients at high risk for ASCVD, but it remains unknown whether the level of kidney function is a risk factor for ASCVD outcomes in the community.MethodsCox proportional-hazards regression was used to evaluate the association of glomerular filtration rate (GFR) with ASCVD after adjustment for the major ASCVD risk factors in 15,350 subjects. We searched for nonlinear relationships between GFR and ASCVD.ResultsDuring a mean follow-up time of 6.2 years, 965 (6.3%) of subjects had ASCVD events. Subjects with GFR of 15 to 59 ml/min/1.73 m2(n = 444, hazard ratio 1.38 [1.02, 1.87]) and 60 to 89 ml/min/1.73 m2(n = 7,665, hazard ratio 1.16 [1.00, 1.34]) had an increased adjusted risk of ASCVD compared with subjects with GFR of 90 to 150 ml/min/1.73 m2. Each 10 ml/min/1.73 m2lower GFR was associated with an adjusted hazard ratio of 1.05 (1.02, 1.09), 1.07 (1.01, 1.12), and 1.06 (0.99, 1.13) for ASCVD, de novo ASCVD, and recurrent ASCVD, respectively. A nonlinear model did not fit the data better than a linear model.ConclusionsThe level of GFR is an independent risk factor for ASCVD and de novo ASCVD in the ARIC study

Detection of Mycobacterium avium subsp. paratuberculosis in an Egyptian mixed breeding farm and comparative molecular characterisation of isolates from cattle, camels and cats – a case report

The present study records and investigates an outbreak of Johne’s Disease in a mixed breeding camel – cattle farm and the possible role of non-domestic non-ruminants animals in the epidemiology of Mycobacterium avium subspecies paratuberculosis in Egypt. For this reason, faecal samples were collected from 24 dairy cattle and from 15 one humped Arabian camels suffering from diarrhoea. Moreover, intestinal tissue samples were provided from 7 cats and 2 rats that were caught from the same farm and were euthanized before necropsy. Samples were examined using traditional culture and IS900 PCR techniques together with the application of BstEII-IS900 RFLP for typing of obtained isolates. Interestingly, MAP was recovered from cattle (n=8) and from camels (n=3) and non-domestic cats (n=3) reared under local conditions in this farm in Egypt. The obtained results highlight the potential role of cats in the epidemiology of MAP, a subject which needs further investigation and might have a public health importance, catsbeing common members of many families

Effect of enalapril on myocardial infarction and unstable angina in patients with low ejection fractions

An association between raised renin levels and myocardial infarction has been reported. We studied the effects of enalapril, an angiotensin-converting enzyme (ACE) inhibitor, on the development of myocardial infarction and unstable angina in 6797 patients with ejection fractions Patients were randomly assigned to placebo (n=3401) or enalapril (n=3396) at doses of 2[middle dot]5-20 mg per day in two concurrent double-blind trials with the same protocol. Patients with heart failure entered the treatment trial (n=2569) and those without heart failure entered the prevention trial (n=4228). Follow-up averaged 40 months. In each trial there were significant reductions in the number of patients developing myocardial infarction (treatment trial: 158 placebo vs 127 enalapril, PEnalapril treatment significantly reduced myocardial infarction, unstable angina, and cardiac mortality in patients with low ejection fractions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29729/1/0000065.pd

CKD classification based on estimated GFR over three years and subsequent cardiac and mortality outcomes: a cohort study

<p>Abstract</p> <p>Background</p> <p>It is unknown whether defining chronic kidney disease (CKD) based on one versus two estimated glomerular filtration rate (eGFR) assessments changes the prognostic importance of reduced eGFR in a community-based population.</p> <p>Methods</p> <p>Participants in the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study were classified into 4 groups based on two eGFR assessments separated by 35.3 ± 2.5 months: sustained eGFR < 60 mL/min per 1.73 m²(1 mL/sec per 1.73 m²); eGFR increase (change from below to above 60); eGFR decline (change from above to below 60); and eGFR persistently ≥60. Outcomes assessed in stratified multivariable Cox models included cardiac events and a composite of cardiac events, stroke, and mortality.</p> <p>Results</p> <p>There were 891 (4.9%) participants with sustained eGFR < 60, 278 (1.5%) with eGFR increase, 972 (5.4%) with eGFR decline, and 15,925 (88.2%) with sustained eGFR > 60. Participants with eGFR sustained < 60 were at highest risk of cardiac and composite events [HR = 1.38 (1.15, 1.65) and 1.58 (1.41, 1.77)], respectively, followed by eGFR decline [HR = 1.20 (1.00, 1.45) and 1.32 (1.17, 1.49)]. Individuals with eGFR increase trended toward increased cardiac risk [HR = 1.25 (0.88, 1.77)] and did not significantly differ from eGFR decline for any outcome. Results were similar when estimating GFR with the CKD-EPI equation.</p> <p>Conclusion</p> <p>Individuals with persistently reduced eGFR are at highest risk of cardiovascular outcomes and mortality, while individuals with an eGFR < 60 mL/min per 1.73 m²at any time are at intermediate risk. Use of even a single measurement of eGFR to classify CKD in a community population appears to have prognostic value.</p

Positive Selection within the Schizophrenia-Associated GABA(A) Receptor β(2) Gene

The gamma-aminobutyric acid type-A (GABA(A)) receptor plays a major role in inhibitory neurotransmissions. Intronic SNPs and haplotypes in GABRB2, the gene for GABA(A) receptor β(2) subunit, are associated with schizophrenia and correlated with the expression of two alternatively spliced β(2) isoforms. In the present study, using chimpanzee as an ancestral reference, high frequencies were observed for the derived (D) alleles of the four SNPs rs6556547, rs187269, rs1816071 and rs1816072 in GABRB2, suggesting the occurrence of positive selection for these derived alleles. Coalescence-based simulation showed that the population frequency spectra and the frequencies of H56, the haplotype having all four D alleles, significantly deviated from neutral-evolution expectation in various demographic models. Haplotypes containing the derived allele of rs1816072 displayed significantly less diversity compared to haplotypes containing its ancestral allele, further supporting positive selection. The variations in DD-genotype frequencies in five human populations provided a snapshot of the evolutionary history, which suggested that the positive selections of the D alleles are recent and likely ongoing. The divergence between the DD-genotype profiles of schizophrenic and control samples pointed to the schizophrenia-relevance of positive selections, with the schizophrenic samples showing weakened selections compared to the controls. These DD-genotypes were previously found to increase the expression of β(2), especially its long isoform. Electrophysiological analysis showed that this long β(2) isoform favored by the positive selections is more sensitive than the short isoform to the inhibition of GABA(A) receptor function by energy depletion. These findings represent the first demonstration of positive selection in a schizophrenia-associated gene